Axle assembly

ABSTRACT

An axle assembly with a housing, an annular gear, a bearing, a differential, and a pair of output shafts. The housing has an annular hub. The annular gear is received in the housing. The bearing, which is a four-point angular contact bearing, supports the gear for rotation about an axis relative to the housing and has an inner bearing race, which is mounted on the annular hub, and an outer bearing race that is fixedly coupled to the annular gear. The differential is received in the housing and includes an input member, which is coupled to the annular gear for rotation therewith, and a pair of output members that are rotatable relative to the input member about the output axis. Each of the output shafts is coupled to an associated one of the output members for rotation therewith. One of the output shafts extends through the annular hub.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 15/470,118 filed Mar. 27, 2017, which is a continuation of U.S. patent application Ser. No. 15/213,602 filed Jul. 19, 2016 (now U.S. Pat. No. 10,975,945 issued Apr. 13, 2021), which is a continuation of U.S. patent application Ser. No. 15/151,831 filed May 11, 2016 (now U.S. Pat. No. 9,593,757 issued Mar. 14, 2017), which is a continuation of U.S. patent application Ser. No. 14/629,614 filed Feb. 24, 2015 (now U.S. Pat. No. 9,677,656 issued Jun. 13, 2017), which is a continuation of U.S. patent application Ser. No. 14/244,117 filed Apr. 3, 2014 (now U.S. Pat. No. 9,103,427 issued Aug. 11, 2015), which is a continuation of U.S. patent application Ser. No. 14/205,535 filed Mar. 12, 2014 (now U.S. Pat. No. 9,157,515 issued Oct. 13, 2015), which claims the benefit of U.S. Provisional Patent Application No. 61/787,547 filed Mar. 15, 2013. The disclosure of each of the above-identified patent applications is incorporated by reference as if fully set forth in detail herein.

FIELD

The present disclosure relates to an axle assembly.

BACKGROUND

This section provides background information related to the present disclosure which is not necessarily prior art.

Modern automotive vehicles, particularly light trucks, typically employ beam axles that are constructed in the style of a Banjo-type axle or a Salisbury-type axle. As is known in the art, a Banjo-type axle employs a housing that is fabricated of two identical beam halves, which are welded to one another on the front and rear edges where the beam halves abut one another. A housing for a conventional Banjo-type axle is disclosed in U.S. Pat. No. 2,674,783. As is also known in the art, a Salisbury-style axle employs a housing that includes a center carrier and a pair of axle tubes that are pressed into or otherwise permanently affixed to the center carrier. A housing for a Salisbury-type axle is disclosed in U.S. Pat. No. 7,878,059.

While such axle housings are satisfactory for their intended purposes, there remains a need in the art for an improved axle assembly.

SUMMARY

This section provides a general summary of the disclosure, and is not a comprehensive disclosure of its full scope or all of its features.

In one form, the present teachings provide an axle assembly that includes a housing, an input pinion, a ring gear, a ring gear bearing and a pair of axle shafts. The input pinon is mounted to the axle housing for rotation about a first axis. The ring gear is received in the axle housing and is meshingly engaged with the input pinion. The ring gear bearing supports the ring gear for rotation relative to the housing about a second axis. The ring gear bearing has a plurality of bearing elements and is abutted against a shoulder formed on the axle housing that is positioned along the second axis at a location that is between the first axis and the first bearing elements. The differential assembly has a differential case, which is coupled to the ring gear for rotation therewith, and a pair of output members. Each of the axle shafts is coupled for rotation with a corresponding one of the output members. Power transmission between the input pinon and the ring gear that drives the ring gear about the second axis in a first rotary direction generates a first thrust load that is directed along the second axis in a first direction. Power transmission between the input pinion and the ring gear that drives the ring gear about the second axis in a second rotary direction opposite the first rotary direction generates a second thrust load that is directed along the second axis in a second direction that is opposite the first direction. Each of the first and second thrust loads is transmitted through the first bearing elements when the first and second thrust loads are transmitted between the ring gear and the housing.

In another form, the present teachings provide an axle assembly that includes a housing, an input pinion, a ring gear, a differential assembly, and a ring gear bearing. The input pinion has a pinion gear and is received in the housing for rotation about a first axis. The ring gear is meshed with the pinion gear and is rotatable about a second axis that is transverse to the first axis. The differential assembly has a differential case and a pair of output members. The differential case is driven by the ring gear. The ring gear bearing supports the ring gear for rotation relative to the housing about the second axis. The ring gear bearing has a plurality of bearing elements, an inner race and an outer race. A bearing groove is formed into the ring gear. The bearing elements are received into the bearing groove such that the outer bearing race is unitarily and integrally formed with the ring gear.

In some forms of this axle assembly, (a) the bearing elements comprise bearing balls; (b) the ring gear bearing can be an angular contact bearing; (c) the ring gear bearing can be a four-point contact bearing; (d) the inner race can include a first inner race member and a second inner race member that are axially separated from one another along the second axis; (e) the axle assembly can further include a bearing adjuster that can be threadably coupled to the housing and configured to move the first inner bearing race member axially toward the second inner bearing race member to pre-load the ring gear bearing; (f) the outer race can include a first outer race member and a second outer race member that can be axially separated from one another along the second axis; (g) the housing can have a first housing member and a second housing member that contact one another in a housing plane that is perpendicular to the second axis; (h) the second housing member can be configured to apply a force that is transmitted through the first outer bearing race to preload the ring gear bearing; (i) the differential assembly can include a differential gearset having a plurality of differential pinions and a pair of side gears that are meshed with the differential pinions; (j) a ball bearing having a plurality of bearing balls can support the input pinion for rotation relative to the housing, the differential pinions can be disposed about differential pinion axes for rotation relative to the differential case, the differential pinion axes can be disposed in a first bearing plane, and the first bearing plane can be located along the second axis between a second bearing plane extending through centers of the bearing balls of the ring gear and a plane extending perpendicular to the second axis and through one of the bearing balls of the ball bearing that supports the input pinion that is closest to the first bearing plane; (k) each of the differential pinions can have a pinion shaft that is received into a mount structure defined by the differential case; (l) the ring gear can support the differential case for rotation relative to the housing; (m) the differential case can be directly engaged to the ring gear such that rotary power is transmitted directly from the ring gear to the differential case; (n) the differential assembly can include a differential gearset having a plurality of differential pinions and a pair of side gears that are meshed with the differential pinions; (o) the differential pinions can be directly engaged to the ring gear such that rotary power is transmitted directly from the ring gear to the differential pinions; (p) at least a portion of the differential pinions are mounted on a cross-pin for rotation and the cross-pin is directly engaged to the ring gear such that rotary power is transmitted directly from the ring gear to the cross-pin; (q) at least a portion of the differential assembly can be supported for rotation relative to the housing on a pair of differential bearings, and a first one of the differential bearings is intersected by a plane that extends through a center of the bearing elements in the ring gear bearing; (r) the housing can have a first housing member and a second housing member that can adjoin one another about a plane that is perpendicular to the second axis; and/or (s) the differential case can be formed of sheet metal.

In still another form, the present teachings provide an axle assembly that includes a housing, an input pinion, a ring gear and a differential assembly. The input pinion has a pinion gear. The input pinion is received in the housing and is rotatable about a first axis. The ring gear is meshed with the pinion gear and is rotatable about a second axis that is transverse to the first axis. The differential assembly has a differential gearset and a differential case. The differential gearset has a plurality of bevel pinions and a pair of side gears that are meshingly engaged to the bevel pinions. The differential case has a case member and a plurality of pinion mounts. A first axial end of the case member is fixed to the ring gear for rotation therewith. The pinion mounts are assembled to the case member. The pinion mounts are non-rotatably coupled to the case member and are configured to support the bevel pinions for rotation relative to the case member about respective bevel pinion axes.

In yet another form, the present teachings provide an axle assembly that includes a housing, an input pinion, a ring gear, a differential assembly, a head bearing and a tail bearing. The input pinion has a pinion gear and a pinion shaft. The input pinion is received in the housing and is rotatable about a first axis. The ring gear is meshed with the pinion gear and is rotatable about a second axis that is transverse to the first axis. The differential assembly has a differential case and a pair of output members. The differential case is driven by the ring gear. The head and tail bearings support the input pinion for rotation relative to the housing about the first axis. The head bearing and the tail bearing are disposed along the first axis on opposite sides of the pinion gear. The tail bearing is configured to handle loads directed along the first axis from the input pinion to the housing in a direction from the head bearing to the tail bearing. The tail bearing comprises an inner bearing race, which is defined by a bearing groove that is formed into the pinion shaft, and a plurality of bearing elements that are received into the bearing groove such that an inner bearing race of the tail bearing is unitarily and integrally formed with the pinion shaft.

In still another form, the present teachings provide an axle assembly that includes a housing, an input pinion, a ring gear, a differential assembly, a head bearing and a tail bearing. The input pinion has a pinion gear and a pinion shaft. The input pinion is received in the housing and is rotatable about a first axis. The ring gear is meshed with the pinion gear and is rotatable about a second axis that is transverse to the first axis. The differential assembly has a differential case and a pair of output members. The differential case is driven by the ring gear. The head and tail bearings support the input pinion for rotation relative to the housing about the first axis. The head bearing is disposed on a first axial end of the input pinion. The tail bearing is a four-point contact ball bearing having a plurality of bearing elements, an inner race and an outer race. The pinion gear is disposed axially between the tail bearing and the head bearing. A bearing groove is formed into the pinion shaft and the bearing elements are received into the bearing groove such that the inner bearing race is unitarily and integrally formed with the pinion shaft.

In some forms of this axle assembly, (a) the pinion mounts can be slidable relative to the case member in an axial direction along the second axis; (b) the housing has a first housing member and a second housing member that adjoin one another about a plane that is perpendicular to the second axis; (c) the axle assembly includes a pair of axle shafts and each of the side gears is axially and non-rotatably coupled to a corresponding one of the axle shafts; (d) each of the axle shafts has a threaded inboard portion and wherein a threaded fastener engages the threaded inboard portion to axially fix an associated one of the side gears to the threaded inboard portion; (e) the threaded fasteners comprise nuts; (f) the axle assembly further includes a pair of inboard axle shaft bearings, each of the inboard axle shaft bearings supporting an associated one of the axle shafts for rotation relative to the housing, and wherein each of the threaded fasteners produces a preload force that is transmitted through the associated one of the side gears and into an associated one of the inboard axle shaft bearings; (g) the axle assembly further includes a pair of outboard axle shaft bearings, each of the outboard axle shaft bearings supporting a corresponding one of the axle shafts; (h) each axle shaft includes a shaft member and a wheel flange that is welded to an axial end of the shaft member; (i) each axle shaft comprises a wheel flange having a shoulder formed thereon, and wherein the outboard axle shaft bearings are abutted against the shoulders; (j) the axle assembly further includes a pair of outboard axle shaft seals, each of the outboard axle shaft seals being sealingly engaged to the housing and a corresponding one of the wheel flanges; (k) axial positioning of the pinion mounts along the second axis is based in part on positions of the side gears along the second axis relative to the housing and an amount by which the side gears are axially separated from one another along the second axis; (l) the case member defines a set of teeth that are disposed parallel to the second axis and wherein the pinion mounts define a plurality of mating teeth that matingly engage the set of teeth defined by the case member; (m) the pinion mounts are formed of plastic; (n) the pinion mounts are formed of powdered metal; (o) the pinion mounts are formed of cast metal; and/or (p) the case member is welded to the ring gear.

In yet another form, the present disclosure provides an axle assembly that includes a carrier housing, an input pinion, a ring gear, a case, a first bearing assembly, a second bearing assembly and a third bearing assembly. The input pinion, which has a plurality of pinion teeth, is received in the carrier housing and is rotatable about a first axis. The ring gear is received in the carrier housing and is rotatable about a second axis that is not parallel to the first axis. The ring gear has a plurality of ring gear teeth. The case is received in the carrier housing and is coupled to the ring gear for rotation about the second axis. The first bearing assembly supports the input pinion for rotation about the first axis relative to the carrier housing. The first bearing assembly has a first outer bearing race that is mounted to the carrier housing at a location along the first axis between the case and the ring gear teeth. The second bearing assembly supports the input pinion for rotation about the first axis relative to the carrier housing. The second bearing assembly is disposed along the first axis on a side of the pinion teeth that is opposite the first bearing. The third bearing assembly supports the ring gear for rotation about the second axis relative to the carrier housing. The third bearing assembly is disposed along the second axis on a side of the ring gear teeth that is opposite the first axis.

In a further form, the present disclosure provides an axle assembly that includes a housing, an input pinion, a ring gear, a differential assembly and first and second bearings. The input pinion has a pinion gear and a pinion shaft. The input pinion is received in the housing and is rotatable about a first axis. The ring gear is meshed with the pinion gear and is rotatable about a second axis that is transverse to the first axis. The differential assembly has a differential input and a pair of output members. The differential input is driven by the ring gear. The first and second bearings support the input pinon for rotation relative to the housing about the first axis. The first bearing is a four-point angular contact bearing having a first outer bearing race, a first inner bearing race and a single row of bearing elements that are disposed between the first outer bearing race and the first inner bearing race.

In still another form, the present disclosure provides an axle assembly that includes a housing, an input pinion, a ring gear, a differential assembly and first and second bearings. The input pinion has a pinion gear and a pinion shaft. The input pinion is received in the housing and is rotatable about a first axis. The ring gear is meshed with the pinion gear and is rotatable about a second axis that is transverse to the first axis. The differential assembly has a differential input and a pair of output members. The differential input is driven by the ring gear. The first and second bearings support the input pinon for rotation relative to the housing about the first axis. Rotation of the input pinion in a first rotational direction to drive the ring gear generates a first thrust force that is transmitted between the input pinion and the housing in a first direction along the first axis. Rotation of the input pinion in a second rotational direction opposite the first rotational direction to drive the ring gear generates a second thrust force that is transmitted between the input pinion and the housing in a second direction along the first axis. At least a substantial majority of each of the first and second thrust forces is transmitted through the first bearing.

Further areas of applicability will become apparent from the description provided herein. The description and specific examples in this summary are intended for purposes of illustration only and are not intended to limit the scope of the present disclosure.

DRAWINGS

The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present disclosure.

FIG. 1 is a schematic illustration of an exemplary vehicle having a (rear) axle assembly constructed in accordance with the teachings of the present disclosure;

FIG. 2 is a longitudinal section view of the axle assembly of FIG. 1;

FIG. 3 is an enlarged portion of FIG. 2, illustrating an input pinion, a ring gear, a differential assembly and a portion of an axle housing in more detail;

FIG. 4 is an exploded perspective view of a portion of the axle assembly of FIG. 1, illustrating the input pinion, a head bearing and a tail bearing in more detail;

FIG. 4A is a longitudinal sectional view of the input pinion shown in FIG. 4;

FIG. 4B is an enlarged view of a portion of FIG. 4B;

FIG. 5 is a section view taken along the line 5-5 of FIG. 3;

FIG. 6 is an enlarged portion of FIG. 2, illustrating a wheel end of the axle assembly in more detail;

FIG. 7 is a view similar to that of FIG. 2 but illustrating another axle assembly constructed in accordance with the teachings of the present disclosure;

FIG. 8 is an enlarged portion of FIG. 7, illustrating an input pinion, a ring gear, a differential assembly and a portion of an axle housing in more detail;

FIG. 9 is an enlarged portion of FIG. 7, illustrating a wheel end of the axle assembly in more detail;

FIGS. 10 and 11 are views similar to that of FIG. 3 but illustrating two other axle assemblies constructed in accordance with the teachings of the present disclosure; and

FIGS. 12 and 13 are left and right side perspective views of a portion of a differential assembly constructed in accordance with the teachings of the present disclosure;

FIG. 14 is a perspective view of a portion of an axle housing constructed in accordance with the teachings of the present disclosure;

FIGS. 15 through 17 are views similar to that of FIG. 6 but illustrating three other axle assemblies constructed in accordance with the teachings of the present disclosure;

FIG. 18 is a section view of a portion of another axle assembly constructed in accordance with the teachings of the present disclosure;

FIG. 19 is a perspective view of a portion of the axle assembly of FIG. 18, illustrating a lock plate and a first locking dog in more detail;

FIG. 20 is a perspective view of a portion of the axle assembly of FIG. 18, illustrating a pinion mount structure and a second locking dog in more detail;

FIG. 21 is a perspective view of a portion of the axle assembly of FIG. 18, illustrating a portion of a locking mechanism in more detail;

FIG. 22 is a perspective view of a portion of the axle assembly of FIG. 18, illustrating the interlocking of adjacent pinion mount structures;

FIG. 23 is a perspective view of a portion of another axle assembly constructed in accordance with the teachings of the present disclosure;

FIG. 24 is a stepped section view of the axle assembly of FIG. 23, having a first portion taken through a hypoid axis of an input pinion parallel to a rotational axis of a differential assembly, and a second portion taken through the rotational axis of the differential assembly parallel to the hypoid axis;

FIG. 24A is a longitudinal section view of a portion of another axle assembly constructed in accordance with the teachings of the present disclosure;

FIG. 25 is a longitudinal section view of a portion of yet another axle assembly constructed in accordance with the teachings of the present disclosure, the view depicting the mounting of the ring gear on inner and outer ring gear bearings; and

FIG. 26 is a longitudinal section view of a portion of still another axle assembly constructed in accordance with the teachings of the present disclosure, the view depicting the mounting of the ring gear on a pair of inner ring gear bearings.

Corresponding reference numerals indicate corresponding parts throughout the several views of the drawings.

DETAILED DESCRIPTION

With reference to FIG. 1 of the drawings, an exemplary vehicle having an axle assembly (e.g., a rear axle assembly) constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral 10. The vehicle 10 can have a power train 12 and a drive line or drive train 14. The power train 12 can be conventionally constructed and can comprise a power source 16 and a transmission 18. The power source 16 can be configured to provide propulsive power and can comprise an internal combustion engine and/or an electric motor, for example. The transmission 18 can receive propulsive power from the power source 16 and can output power to the drive train 14. The transmission 18 can have a plurality of automatically or manually-selected gear ratios. The drive train 14 in the particular example provided is of a two-wheel, rear-wheel drive configuration, but those of skill in the art will appreciate that the teachings of the present disclosure are applicable to other drive train configurations, including four-wheel drive configurations, all-wheel drive configurations, and front-wheel drive configurations. The drive train 14 can include a prop shaft 20 and a rear axle assembly 22. The propshaft 20 can couple the transmission 18 to the rear axle assembly 22 such that rotary power output of the transmission 18 is received by the rear axle assembly 22. The rear axle assembly 22 can distribute the rotary power to the rear vehicle wheels 26.

With reference to FIGS. 2 and 3, the rear axle assembly 22 can include a housing 30, an input pinion 32, a ring gear 34, a differential assembly 36, and a pair of axle shafts 38. The input pinion 32 can be rotatable about a first axis 40, while the ring gear 34 and the differential assembly 36 can be rotatable about a second axis 42 that can be transverse (e.g., perpendicular) to the first axis 40.

With reference to FIG. 3, the housing 30 can comprise first and second housing structures 46 and 48, respectively, that can be fixedly but removably coupled to one another. The first and second housing structures 46 and 48 can cooperate to define a differential cavity 50 into which the differential assembly 36 can be received.

The first housing structure 46 can comprise a first carrier member 54 and a first axle tube 56. The first carrier member 54 can be formed of an appropriate material, such as cast iron or aluminum, and can define a pinion bore 58, a first tube collar 60, and a first joint flange 62. The pinion bore 58 can extend along the first axis 40 and can be configured to receive the input pinion 32. The first tube collar 60 can be a tubular structure that can be configured to receive the first axle tube 56. The first axle tube 56 can be a hollow structure that can be press-fit into the first tube collar 60. One or more slug welds (not shown) can be employed to inhibit axial and/or radial movement of the first axle tube 56 relative to the first carrier member 54.

The second housing structure 48 can comprise a second carrier member 64 and a second axle tube 66. The second carrier member 64 can be formed of an appropriate material, such as sheet or plate steel, and can define a second tube collar 70 and a second joint flange 72. The second tube collar 70 can be a tubular structure that can be configured to receive the second axle tube 66. A plurality of threaded fasteners 76 (only one shown) can be employed to fixedly but removably couple the second carrier member 64 to the first carrier member 54 such that the first and second joint flanges 62 and 72 abut or adjoin one another in a plane that is perpendicular to the second axis 42. In the particular example provided, the threaded fasteners 76 are thread-forming screws that are received through holes (not specifically shown) in the second joint flange 72 and driven into holes (not specifically shown) in the first joint flange 62 to both form threads in the first carrier member 54 (on their initial installation to the first carrier member 54) and to generate a clamp load that secures the first and second carrier members 54 and 64 to one another. A seal member, such as a gasket 80, can be disposed between and sealingly engaged to the first and second carrier members 54 and 64. The second axle tube 66 can be a hollow structure that can be received in the second tube collar 70 and fixedly coupled to the second carrier member 64. In the particular example provided, the second axle tube 66 is welded to the second tube collar 70.

With reference to FIGS. 3 and 4, the input pinion 32 can include a pinion gear 90 and a pinion shaft 92 that can be fixed to and rotate with the pinion gear 90. In the particular example provided, the pinion gear 90 and the pinion shaft are integrally and unitarily formed from a single piece of steel. The input pinion 32 can be received in the pinion bore 58 in the housing 30 and can be supported for rotation relative to the housing 30 about the first axis 40 by a head bearing 96, which can be disposed on a first axial end of the input pinion 32, and a tail bearing 98 that can be disposed on a second, opposite axial end of the input pinion 32. The pinion gear 90 can be disposed along the first axis 40 axially between the head bearing 96 and the tail bearing 98.

The head bearing 96 can comprise a plurality of bearing elements 100, an inner bearing race 102 and an outer bearing race 104. The bearing elements 100 can be any type of element that can roll relative to the inner and outer and inner bearing races 102 and 104. In the particular example provided, the bearing elements 100 are cylindrically-shaped rollers. The inner bearing race 102 can be formed on a cylindrical extension 110 that extends from the pinion gear 90 on a side opposite the pinion shaft 92. The bearing elements 100 of the head bearing 96 can be in direct contact with the cylindrical surface of the cylindrical extension 110. The outer bearing race 104 can be received in a pocket 114 formed in the first carrier member 54 and fixedly coupled the first carrier member 54 (e.g., via a press-fit).

The tail bearing 98 can have a plurality of bearing elements 120, an inner bearing race 122 and an outer bearing race 124. The bearing elements 120 can be any type of element that can roll relative to the inner and outer bearing races 122 and 124. In the particular example provided, the bearing elements 120 comprise bearing balls. The inner bearing race 122 can comprise a bearing groove 130 that can be formed into a desired portion of the input pinion 32, such as the pinion shaft 92. The bearing elements 120 can be received into the bearing groove 130 such that the inner bearing race 122 is unitarily and integrally formed with the pinion shaft 92. The outer bearing race 124 can be received in a bearing bore 136 formed in the first carrier member 54. The tail bearing 98 can be an angular contact bearing, but in the particular example provided, the tail bearing 98 is a four-point contact ball bearing in which the bearing balls make contact at two points with the surface of the bearing groove 130 and with first and second outer race members 140 and 142, respectively, which cooperate to form the outer race 124. The first outer race member 140 can be axially separated from the second outer race member 142 along the first axis 40. A bearing adjuster 150 can be threadably engaged to the first carrier member 54 and can be configured to move the first outer bearing race member 140 toward the second outer bearing race member 142 to preload the tail bearing 98. The bearing adjuster 150 can be formed of sheet steel and can have a threaded outside diameter 152 and a hollow tool engaging portion 154 through which the pinion shaft 92 can extend. The tool engaging portion 154 has an octagonal shape in the example provided, which permits the bearing adjuster 150 to be installed using a socket wrench. The bearing adjuster 150 can be deformable to allow a portion of it to be staked into a recess formed in the first carrier member 54 to inhibit rotation of the bearing adjuster 150 after the preload on the tail bearing 98 has been set.

With specific reference to FIG. 4, the input pinion 32 can define an internal cavity 160, which can extend through the pinion shaft 92 on a side opposite the pinion gear 90, and a first coupling portion 162 that can be fixedly and non-rotatably coupled to a second coupling portion 164 on a yoke flange 166. In the example provided, the first coupling portion 162 comprises a plurality of internal spline teeth that border the internal cavity 160. The internal spline teeth of the first coupling portion 162 can be configured to matingly engage external spline teeth formed on the second coupling portion 164. An axial retaining means, such as a snap ring, a screw or one or more stakes formed in a staking operation, can be employed to retain the yoke flange 166 to the input pinion 32. For example, a snap ring 168 can be received in a groove 170 in the second coupling portion 164 and abutted against a feature, such as a shoulder 174, on the first coupling portion 162 to thereby axially fix the second coupling portion 164 to the first coupling portion 162. It will be appreciated, however, that the axial retaining means used in addition to the internal and (mating) external spline teeth is optional. It will also be appreciated that other means for retaining the yoke flange 166 to the input pinion 32 could be employed, such as a plurality of barbs or serrations on one or both of the yoke flange 166 and the input pinion 32.

If desired, the second coupling portion 164 on the yoke flange 166 could be formed by pressing a pin portion 900 of the yoke flange 166 into the internal cavity 160. For example, the input pinion 32 could be sufficiently hardened (steel) and pin portion 900 of the yoke flange 166 could be formed a relatively softer material, such as an unhardened steel or aluminum, which could deform as the pin portion 900 is pressed into the internal cavity 160. In some instances, the input pinion 32 could function as a broach-like tool that machines the pin portion 900 as it is inserted into the internal cavity 160. With additional reference to FIGS. 4A and 4B, the internal cavity 160 and the internal spline teeth 902 of the first coupling portion 162 can cooperate to form a structure that is configured to both machine mating external spline teeth onto the yoke flange 166 and to contain the chips or swarf that is formed when the mating external spline teeth are formed. Each of the internal spline teeth 902 can be formed with a frustoconically-shaped face 904 that tapers away from a rear end 906 of the input pinion 32 with increasing distance from the first axis 40. The amount of taper can be about 5 degrees to about 20 degrees (as measured from the frustoconically-shaped face 904 to a line perpendicular to the first axis 40), and preferably about 15 degrees. The radially inward edge 908 of each frustoconically-shaped face 904 can be left sharp, while the radially outward edge of each frustoconically-shaped face 904 can blend into an undercut radius 910 that defines a forward end of an annular chip containment compartment 912. A rearward end of the chip containment compartment 912 can be defined by a radially inwardly extending wall member 914. The radially inwardly extending wall member 914 can be formed in any manner that is desired, such as tapering inwardly toward the first axis 40 with increasing distance from the internal spline teeth 902. The chip containment compartment 912 is a space that is disposed about the pin portion 900 of the yoke flange 166 when the pin portion 900 is pressed into the internal cavity 160 to form the second coupling portion 164. It will be appreciated that the radially inward edges 908 of the frustoconically-shaped faces 904 form broach-like cutting elements and that the frustoconically-shaped faces 904 direct the chips (created when the second coupling portion 164 is formed) in a radially outward direction. The rounded geometry of the undercut radius 910 can urge the chips to curl back gently to lessen the likelihood that the chips jam against the input pinion 32 and possibly impart additional loading when the yoke flange 166 is pressed onto the input pinion 32. The chips generated during the formation of the second coupling portion 164 can be contained in the chip containment compartment 912 between the undercut radius 910 and the radially inwardly extending wall member 914. Preferably, the radially inwardly extending wall member 914 is sufficiently close in diameter to the pin portion 900 so that the radially inwardly extending wall member 914 pilots or aligns the pin portion 900 concentrically to the internal spline teeth 902 (and both fore and aft of the internal spline teeth 902) prior to and during the formation of the mating spline teeth on the second coupling portion 164.

For example, the pin portion 900 of the second coupling portion 164 can comprise first and second portions that are formed on opposite sides of the external spline teeth 164 and the first and second portions of the pin portion 900 can slidingly engage first and second surfaces of the internal cavity 160 over distances that are longer along the first axis 40 than a length of the internal spline teeth 902. Also preferably, the radially inwardly extending wall member 914 is sufficiently close in diameter to the pin portion 900 so that the radially inwardly extending wall member 914 forms a barrier that inhibits the egress of chips from a rearward end of the chip containment compartment 912.

Coupling of the yoke flange 166 to the input pinion 32 can be performed, for example, after the input pinion 32 has been installed to the first carrier member 54 and is supported by the tail bearing 98. So that the load associated with the pressing of the yoke flange 166 to the input pinion 32 is not directed to the bearing elements 120 of the tail bearing 98, the input pinion 32 could be supported by an anvil (not shown) that could be received through a hole (not shown) formed in the first carrier member 54 (FIG. 3). The anvil could be removed after the yoke flange 166 has been pressed to the input pinion 32 and the hole in the first carrier member 54 (FIG. 3) could be plugged. The hole could have other uses, such as for inspection of a portion of the axle assembly 22 (FIG. 2) and/or for filling the first carrier member 54 (FIG. 3) with a lubricant, and as such, the plug could be removably coupled to the first carrier member 54 (FIG. 3). Alternatively, the pin portion 900 of the yoke flange 166 can be hollow and a tool, which can be threaded into a threaded hole 324 in the input pinion 32, could be employed to force the yoke flange 166 and the input pinion 32 together (e.g., hydraulically). Moreover, a bolt (not shown) could be inserted through a hole (not shown) in the yoke flange 166 and threadably engaged to the threaded hole 324 in the input pinion 32 to axially and/or rotationally fix the yoke flange 166 to the input pinion 32.

Returning to FIG. 3, a pinion shaft seal 180 can be received between the housing 30 and the pinion shaft 92 of the input pinion 32. In the particular example provided, the pinion shaft seal 180 comprises an annular connection member 182, which is fixedly and sealingly engaged to a tubular portion 184 of the first carrier member 54, and a seal member 186 that is fixed to an internal end of the connection member 182. The seal lip 186 can comprise one or more sealing lips that can be sealingly engaged to the pinion shaft 92. One or more of the sealing lips on the seal member 186 can be received axially through the bearing adjuster 150 and sealingly engaged to the pinion shaft 92. Alternatively, the pinion shaft seal 180 could sealingly engage against a portion of the yoke flange 166.

If desired, a bearing shield 190 can be employed to cover an axial end of the pinion shaft seal 180. In the particular example provided, the bearing shield 190 is unitarily and integrally formed with the yoke flange 166 and includes a radial member 192, which extends radially outwardly from the second coupling portion 164, and a tubular member 194 that can be coupled to a distal end of the radial member 192 and extend axially toward the pinion gear 90.

The ring gear 34 can be meshed with the pinion gear 90 and is rotatable about the second axis 42. A ring gear bearing 200 can support the ring gear 34 for rotation relative to the housing 30 about the second axis 42. The ring gear bearing 200 can comprise a plurality of bearing elements 202, an outer bearing race 204, and an inner bearing race 206. The bearing elements 202 can be any type of element that can roll relative to the inner and outer bearing races 206 and 204. In the particular example provided, the bearing elements 202 comprise bearing balls. The outer bearing race 204 can comprise a bearing groove 210 that can be formed into a desired portion of the ring gear 34, such as the in the toe or inside diametrical surface of the ring gear 34. The bearing elements 202 can be received into the bearing groove 210 such that the outer bearing race 204 is unitarily and integrally formed with the ring gear 34. The inner bearing race 206 can be received on a hub 212 formed on the first carrier member 54. The ring gear bearing 200 can be an angular contact bearing, but in the particular example provided, the ring gear bearing 200 is a four-point contact ball bearing in which the bearing balls make contact at two points with the surface of the bearing groove 210 and with first and second inner race members 220 and 222, respectively, which cooperate to form the inner bearing race 206. The first inner race member 220 can be axially separated from the second inner race member 222 along the second axis 42.

A bearing adjuster 226 can be threadably engaged to the hub 212 and can be configured to move the first inner bearing race member 220 toward the second inner bearing race member 222 to preload the ring gear bearing 200. The bearing adjuster 226 can be formed of sheet steel and can have a threaded inside diameter 228, which can be threadably engaged to the hub 212, and a hollow tool engaging portion 230. The tool engaging portion 230 has an octagonal shape in the example provided, which permits the bearing adjuster 226 to be installed using a socket wrench. The bearing adjuster 226 can be deformable to allow a portion of it to be staked into a recess formed in the first carrier member 54 to inhibit rotation of the bearing adjuster 226 after the preload on the ring gear bearing 200 has been set.

With reference to FIGS. 3 and 5, the differential assembly 36 can include a differential case 240, a pair of output members 242 and a means 246 for permitting speed differentiation between the output members 242. The differential case 240 can comprise a case member 250 and a plurality of pinion mount structures 252. The case member 250 can be formed of an appropriate material, such as sheet or plate steel, and can define a ring gear flange 258 and a coupling portion 260. The ring gear flange 258 can be fixedly coupled to the ring gear 34 in any desired manner, such as with a plurality of threaded fasteners (not shown). In the example provided, the ring gear flange 258 is welded to the heel of the ring gear 34. The case member 250 can taper in a generally frustoconical manner between the ring gear flange 258 and the coupling portion 260. The coupling portion 260 can be a generally tubular structure that can be non-rotatably engaged to the pinion mount structures 252 in any desired manner. In the example provided, the coupling portion 260 includes a plurality of circumferentially spaced-apart spline teeth 264 that are formed parallel to and about the second axis 42.

The pinion mount structures 252 can be shaped in the form of annular segments and can nest together to form an annular structure that can be received into the coupling portion 260. The pinion mount structures 252 can be formed of a suitable material, such as a plastic (e.g., glass-filled Nylon), a powdered metal or a cast metal (e.g., die cast metal). Each of the pinion mount structures 252 can include a plurality of spline teeth 274 and a mount structure 276 that can be configured to transmit rotary power to the speed differentiation means 246. The spline teeth 274 can be formed on an exterior circumferential surface of the pinion mount structures 252 and can be configured to matingly engage the spline teeth 264 of the coupling portion 260.

The speed differentiation means 246 can comprise any means for permitting speed differentiation between the output members 242. For example, the speed differentiation means 246 can include one or more clutches, such as friction clutches (not shown), that can be operated to permit/control speed differentiation between the output members 242. In the particular example provided, the speed differentiation means 246 comprises a differential gearset 280 having a plurality of differential pinions 282 and a pair of side gears 284. Each of the differential pinions 282 can include a pinion member 290 and a mating mount structure 292 that is configured to engage the mount structure 276 of an associated one of the pinion mount structures 252 to receive rotary power therefrom. The pinion members 290 can be bevel pinion gears that can meshingly engage the side gears 284. Each of the output members 242 can be fixedly and non-rotatably coupled to an associated one of the side gears 284. Each of the output members 242 can comprise an internally splined structure that can be mounted on a corresponding one of the axle shafts 38.

In the example provided, the mating mount structures 292 are hollow cylindrical shaft members and the mount structures 276 are holes into which the shaft members (mating mount structures 292) are received. Each of the shaft members can be integrally and unitarily formed with an associated one of the pinion members 290. It will be appreciated, however, that the shaft members could be discrete components that can be fixedly coupled to one or more of the pinion members 290. The pinion mount structures 252 can be configured to support the pinion members 290 for rotation relative to the case member about respective bevel pinion axes 298.

The pinion mount structures 252 are slidable relative to the case member 250 in an axial direction along the second axis 42. Axial positioning of the pinion mount structures 252 along the second axis 42 can be based in part on positions of the side gears 284 along the second axis 42 relative to the housing 30 and an amount by which the side gears 284 are axially separated from one another along the second axis 42. Configuration in this manner permits the pinion mount structures 252 to float along the second axis 42 so that the differential gearset 280 can dictate their position.

With reference to FIGS. 3 and 6, each of the axle shafts 38 can be fixedly and non-rotatably coupled to an associated one of the output members 242. Each of the axle shafts 38 can have a shaft member 304 and a wheel flange 306 that can be fixedly coupled to an axial outboard end of the shaft member 304. In the example provided, the shaft member 304 is a hollow tube and is welded to the wheel flange 306 via a suitable welding process, such as friction welding, but it will be appreciated that other fastening means, such as a splined connection that is mechanically fastened (e.g., threaded fasteners), could be employed in the alternative. The shaft member 304 can have an inboard end (shown in FIG. 3), which can include an externally splined structure 310 and a plurality of threads 312, and an outboard end (shown in FIG. 6).

With reference to FIG. 3, the externally splined structure 310 can be configured to matingly engage the internally splined structure on an associated one of the output members 242. A threaded fastener 320 can be engaged to the plurality of threads 312 to axially fix an associated one of the output members 242 to a corresponding one of the shaft members 304. The plurality of threads 312 can be external threads that can be formed inboard of the externally splined structure 310 and the threaded fastener 320 can comprise a nut. Any desired means can be employed to inhibit rotational movement of the nut relative to the axle shaft 38, including staking, adhesives, and/or a locking tab.

With reference to FIGS. 3 and 6, each axle shaft 38 can be supported for rotation relative to a corresponding one of the first and second axle tubes 56 and 66 by an inboard axle shaft bearing 330 (FIG. 3) and an outboard axle shaft bearing 332 (FIG. 6). The inboard axle shaft bearing 330 can be any type of bearing, such as a tapered roller bearing, and can include an outer bearing race 340 and an inner bearing race 350 that can be received on an associated one of the shaft members 304 and abutted against a corresponding one of the output members 242. The outer bearing races 340 can be received into a pocket 342 formed in an inboard axial end of the hub 212 on the first carrier member 54 and a pocket 344 formed in an inboard axial end of the second axle tube 66. In the example provided, each of the threaded fasteners 320 is configured to produce a preload force that is transmitted through one of the side gears 284 and into one of the inboard axle shaft bearings 330.

The outboard axle shaft bearings 332 can be any type of bearing, such as a tapered roller bearing, and can include an outer bearing race 360, which can be received into a pocket 362 formed in an outboard axial end of the first axle tube 56 or the second axle tube 66, and an inner bearing race 364 that can be received on a shaft portion 366 of the wheel flange 306. The inner bearing race 364 can be abutted against a shoulder 370 formed on the wheel flange 306. A pair of outboard axle shaft seals 374 can be employed to form seals between the housing 30 and the axle shafts 38. Each of the axle shaft seals 374 can be received into an associated one of the first and second axle tubes 56 and 66 and can have a lip seal 376 that can be sealingly engaged to a seal surface 378 on the wheel flange 306.

It will be appreciated that as the present example employs tapered roller bearings for the inboard and outboard axle shaft bearings 330 and 332, it is necessary to preload these bearings. While the axle assembly 22 (FIG. 2) may be assembled in various different ways, we presently envision that the axle shafts 38, the output members 242, the inboard and outboard axle shaft bearings 330 and 332, and the threaded fasteners 320 can be assembled to the first and second housing structures 46 and 48 prior to the assembly of the first and second housing structures 46 and 48 to one another. The ring gear 34 and the ring gear bearing 200 can be installed to the first housing structure 46. In either order, the differential pinions 282 can be assembled to the pinion mount structures 252 and the pinion mount structures 252 can be installed to the coupling portion 260 of the differential case 240. The differential pinions 282 can be meshed with the side gear 284 that is coupled to the axle shaft 38 that is mounted in the first housing structure 46. The gasket 80 can be mounted to the first carrier member 54. The second housing structure 48 can be positioned relative to the first housing structure 46 to cause the side gear 284 that is coupled to the axle shaft 38 that is mounted in the second housing structure 48 to mesh with the differential pinions 282. The second joint flange 72 on the second carrier member 64 can be adjoin the first joint flange 62 on the first carrier member 54. Depending on the configuration of the gasket 80, portions of the first and second joint flanges 62 and 72 may actually abut (contact) one another as is the case in the illustrated example. Alternatively, the gasket 80 could be disposed between the first and second joint flanges 62 and 72 so as to inhibit contact between the first and second joint flanges 62 and 72.

It will be appreciated that in the particular example provided, a portion of the differential assembly 36 (e.g., the side gears 284) is supported for rotation relative to the housing 30 via the inboard axle shaft bearing 330 and as such, the inboard axle shaft bearing 330 functions in some degree as differential bearings. The inboard axle shaft bearing 330 in the first housing structure 46 can be disposed relative to the ring gear bearing 200 such that a plane extending through the centers of the bearing elements 202 of the ring gear bearing 200 extends through the inboard axle shaft bearing 330 in the first housing structure 46. Stated another way, the inboard axle shaft bearing 330 can be nested under or in-line with the bearing elements 202 of the ring gear bearing 200.

With reference to FIGS. 7 and 8, a second axle assembly constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral 22 a. The second axle assembly 22 a can be generally similar to the axle assembly 22 (FIG. 2), except for the differential assembly 36 a and the axle shafts 38 a.

With reference to FIG. 8, the differential assembly 36 a can include a differential case 240 a, a pair of output members 242 a and a means 246 a for permitting speed differentiation between the output members 242 a. The differential case 240 a can comprise a first case member 400, a second case member 402 and a third case member 404, each of which being formed of an appropriate material, such as sheet steel. The first case member 400 can define a ring gear flange 258 a and a coupling portion 260 a. The ring gear flange 258 a can be fixedly coupled to the ring gear 34 in any desired manner, such as with a plurality of threaded fasteners (not shown). In the example provided, the ring gear flange 258 a is welded to the ring gear 34. The first case member 250 can taper in a generally frustoconical manner between the ring gear flange 258 a and the coupling portion 260 a. The coupling portion 260 a can be fixedly and non-rotatably coupled to the second case member 402. In the example provided, the coupling portion 260 a is an annular flange member that extends radially inwardly from a distal end of the frustoconical portion of the first case member 400 and is fixedly coupled (e.g., welded) to a radial flange member 410 on the second case member 402. The second and third case members 402 and 404 are identical stampings and as such, only the second case member 402 will be discussed in detail. In addition to the radial flange member 410, the second case member 402 can have a generally spherical body portion 420, which can be disposed within the radial flange member 410, and a plurality of half-mounts 422. The second and third case members 402 and 404 can be fixedly coupled at their radial flange members 410 (e.g., via welding or threaded fasteners) such that the generally spherical body portions 420 cooperate to define a cavity 430 into which the speed differentiation means 246 a can be received. The second and third case members 402 and 404 are coupled to one another such that the half-mounts 422 cooperate to define tubular mount structures 276 a.

The speed differentiation means 246 a can comprise any means for permitting speed differentiation between the output members 242 a. For example, the speed differentiation means 246 a can include one or more clutches, such as friction clutches (not shown), that can be operated to permit/control speed differentiation between the output members 242 a. In the particular example provided, the speed differentiation means 246 a comprises a differential gearset 280 a having a plurality of differential pinions 282 a and a pair of side gears 284 a. Each of the differential pinions 282 a can include a pinion member 290 a and a shaft member 292 a that is received in and engaged to an associated one of the tubular mount structures 276 a to thereby receive rotary power from the differential case 240 a. The pinion members 290 a can be bevel pinion gears that can meshingly engage the side gears 284 a. Each of the shaft members 292 a can be integrally and unitarily formed with an associated one of the pinion members 290 a. It will be appreciated, however, that the shaft members 292 a could be discrete components that can be fixedly coupled to one or more of the pinion members 290 a. The tubular mount structures 276 a can be configured to support the pinion members 290 a for rotation relative to the case member about respective bevel pinion axes 298. Each of the output members 242 a can be fixedly and non-rotatably coupled to an associated one of the side gears 284 a. Each of the output members 242 a can comprise an internally splined structure that can be mounted on a corresponding one of the axle shafts 38 a.

With reference to FIGS. 8 and 9, each of the axle shafts 38 a can be non-rotatably coupled to an associated one of the output members 242 a. Each of the axle shafts 38 a can have a shaft member 304 a and a wheel flange 306 a that can be fixedly coupled to an axial outboard end of the shaft member 304 a. In the example provided, the shaft member 304 a is a hollow tube and is welded to the wheel flange 306 a via a suitable welding process, such as friction welding. The shaft member 304 a can have an inboard end (shown in FIG. 8), which can include an externally splined structure 310 a, and an outboard end (shown in FIG. 9). The externally splined structure 310 a can be configured to matingly engage the internally splined structure on an associated one of the output members 242 a.

With reference to FIG. 9, each axle shaft 38 a can be supported for rotation relative to a corresponding one of the first and second axle tubes 56 a and 66 a by an outboard axle shaft bearing 332 a. The outboard axle shaft bearings 332 a can be any type of bearing, such as a tapered roller bearing, and can include an outer bearing race 360 a, which can be received into a pocket 362 a formed in an outboard axial end of the first axle tube 56 a or the second axle tube 66 a, and an inner bearing race 364 a that can be received on a shaft portion 366 a of the wheel flange 306 a. An outboard side of the inner bearing race 364 a can be abutted against a shoulder 370 a formed on the wheel flange 306 a and a wedding ring 450, which can be axially fixed to the shaft portion 366 a of the wheel flange 306 a, can be abutted an inboard side of the inner bearing race 364 a. A pair of outboard axle shaft seals 374 a can be employed to form seals between the housing 30 a and the axle shafts 38 a. Each of the axle shaft seals 374 a can be received into an associated one of the first and second axle tubes 56 a and 66 a and can have a lip seal 376 a that can be sealingly engaged to a seal surface 378 a on the wheel flange 306 a.

With renewed reference to FIGS. 8 and 9, it will be appreciated that as the present example employs tapered roller bearings for the outboard axle shaft bearings 332 a, it is necessary to preload these bearings. While the axle assembly 22 a (FIG. 7) may be assembled in various different ways, we presently envision that the outboard axle shaft bearings 332 a are preloaded after the axle assembly 22 a (FIG. 7) has been assembled. The axle assembly 22 a (FIG. 7) can include a preload mechanism 460 that can be configured to apply a compressive force to the inboard axial ends of the axle shafts 38 a. The preload mechanism 460 can comprise any suitable device, such as a jack screw, a suitably sized spacer, or a cylinder. In the particular example provided, the preload mechanism 460 comprises a cylinder 462 and a pair of thrust bearings 464. The cylinder 462 is configured to be filled with an incompressible fluid, such as a grease, that causes the cylinder 462 to elongate and apply a compressive force to the axle shafts 38 a. The grease can be input to the cylinder 462 through a one-way valve, such as a Zerk fitting (not specifically shown). Each of the thrust bearings 464 can be abutted against a side of the cylinder 462 and an axial end of one of the axle shafts 38 a.

In FIG. 10, a portion of a third axle assembly 22 b constructed in accordance with the teachings of the present disclosure is illustrated. The third axle assembly 22 b can be generally similar to the axle assembly 22 a (FIG. 7), except for the housing 30 b, the input pinion 32 b, the ring gear 34 b, the ring gear bearing 200 b and the differential case 240 b. The housing 30 b is generally similar to the housing 30 (FIG. 3), except that the housing 30 b additionally includes a third housing structure 500 that is fixedly but removably coupled to the first carrier member 54 b. The third housing structure 500 comprises an integral bearing seat 150 b that can be configured to move the first outer bearing race member 140 toward the second outer bearing race member 142 when the third housing structure 500 is installed to the first carrier member 54 to preload the tail bearing 98. A gasket 506 can be received between the first carrier member 54 b and the third housing structure 500.

The input pinion 32 b can be generally identical to the input pinion 32 (FIG. 3), except that the yoke flange 166 b can be unitarily and integrally formed with the pinion gear 90 and the pinion shaft 92 b from a single piece of steel. The internal cavity 160 b can extend through the yoke flange 166 b. The pinion shaft seal 180 b can be sealingly engaged to the third housing structure 500 and sealingly engaged to the pinion shaft 92 b of the input pinion 32 b. The bearing shield 190 b can be a discrete component that can be assembled to the input pinion 32 b.

The ring gear 34 can be meshed with the pinion gear 90 and is rotatable about the second axis 42. A ring gear bearing 200 can support the ring gear 34 for rotation relative to the housing 30 about the second axis 42. The ring gear bearing 200 can comprise a plurality of bearing elements 202, an outer bearing race 204, and an inner bearing race 206. The bearing elements 202 can be any type of element that can roll relative to the inner and outer bearing races 206 and 204. In the particular example provided, the bearing elements 202 comprise bearing balls. The outer bearing race 204 can comprise a bearing groove 210 that can be formed into a desired portion of the ring gear 34, such as the in the toe or inside diametrical surface of the ring gear 34. The bearing elements 202 can be received into the bearing groove 210 such that the outer bearing race 204 is unitarily and integrally formed with the ring gear 34. The inner bearing race 206 can be received on a hub 212 formed on the first carrier member 54. The ring gear bearing 200 can be an angular contact bearing, but in the particular example provided, the ring gear bearing 200 is a four-point contact ball bearing in which the bearing balls make contact at two points with the surface of the bearing groove 210 and with first and second inner race members 220 and 222, respectively, which cooperate to form the inner bearing race 206. The first inner race member 220 can be axially separated from the second inner race member 222 along the second axis 42.

The differential case 240 b is similar to the differential case 240 a (FIG. 8) except that the second and third case members 402 b and 404 b are directly coupled to the ring gear 34 b so that the first case member 400 (FIG. 8) is not required. In the particular example provided, the radial flange members 410 b of the second and third case members 402 b and 404 b define a plurality of external teeth 510 that are engaged to internal teeth 512 formed on the inside diametrical surface of the ring gear 34 b. Accordingly, it will be appreciated that rotary power can be transmitted directly from the ring gear 34 b to the differential case 240 b and that the ring gear 34 b supports the differential case 240 b for rotation relative to the housing 30 b.

In the particular example illustrated, the differential pinions 282 a are disposed about differential pinion axes 298 for rotation relative to the differential case 240 b, the differential pinion axes 298 are disposed in a first bearing plane 520, and the first bearing plane 520 is located along the second axis 42 between a second bearing plane 522, which extends through centers of the bearing balls of the ring gear 34 b, and a plane 524 that extends perpendicular to the second axis 42 and through one of the bearing balls of the tail bearing 98 that is located closest to the first bearing plane 520.

In FIG. 11, a portion of a fourth axle assembly 22 c constructed in accordance with the teachings of the present disclosure is illustrated. The fourth axle assembly 22 c can be generally similar to the axle assembly 22 b (FIG. 10), except for the differential assembly 36 c. The differential assembly 36 c includes a differential gearset 280 c having a cross-pin 550 that is received in the mount structure 276 c in the differential case 240 c and into slots 552 formed in the ring gear 34 c. The differential case 240 c is formed of two case halves that are not fixedly coupled to one another in the example provided. Tabs on the case halves can be received into the slots 552 in the ring gear 34 c so that the case halves are rotatably coupled to the ring gear 34 c. The differential pinions 282 c are rotatably mounted on the cross-pin 550. Rotary power can be transmitted directly from the ring gear 34 c to the cross-pin 550 (and to the differential case 240 c). A thrust bearing 556 can be received between the differential case 240 c and the housing 30 c. Proximal ends of the axle shafts 38 c can abut the cross-pin 550. A snap ring 560 can be received in a ring groove 562 in each axle shaft 38 c and the snap ring 560 can abut an inboard surface of a corresponding one of the side gears 284 c. Alternatively, the cross-pin 550 can be deleted and differential pinions similar to the differential pinions 282 a (FIG. 8) can be employed. In this alternative example, the shaft member 292 a (FIG. 8) can be extended somewhat so as to be received into a corresponding one of the slots 552 in the ring gear 34 c so that the differential pinions 282 a (FIG. 8) are directly engaged to the ring gear 34 c such that rotary power is transmitted directly from the ring gear 34 c to the differential pinions 282 a (FIG. 8).

While not shown, the axle shafts 38 c can “float” at the wheel ends. In this regard, the outboard ends of the axle shafts 38 c can be mounted on cylindrical roller bearings. It will be appreciated, however, that other mounting configurations for the axle shafts 38 c could be employed in the alternative.

In FIGS. 12 and 13, a portion of an alternately constructed differential case 240 d is illustrated. The differential case 240 d includes a first case member 250 d with a ring gear flange 258 d that includes a plurality of projections or embossments 570 that are configured to be received into corresponding holes or slots (not shown) in a ring gear (not shown). Threaded fasteners (not shown) can be received through holes 572 in the ring gear flange 258 d and threadably engaged to threaded holes (not shown) in the ring gear.

In FIG. 14, an alternately constructed bearing adjuster 226 d is illustrated as being threadably mounted on a threaded portion of the hub 212 on the first carrier member 54. The bearing adjuster 226 d comprises a plurality of locking features, such as teeth 590, on its outer circumferential surface. A locking bracket 592 can have a mating locking feature, such as mating teeth 594, that can matingly engage the locking features on the bearing adjuster 226. The locking bracket 592 can be fixedly coupled to the first carrier member 54. In the particular example provided, a bolt (not shown) is employed to removably secure the locking bracket 592 to the first carrier member 54.

In the examples of FIGS. 15 through 17, different outboard axle bearing and wheel flange configurations are depicted. In FIG. 15, the outboard axle bearing 332 e has an inner bearing race 364 e that is integrally formed with the shaft portion 366 e of the wheel flange 306 e. The outer bearing race 360 e can comprise first and second race members 600 and 602, which permit bearing elements, such as rollers 604, to be received in an undercut bearing surface 606 on the shaft portion 366 e. A retainer 610 can be employed to retain the axle shaft seal 374 e and the outer bearing race 360 e in the first axle tube 56 e or the second axle tube 66 e.

The example of FIG. 16 is generally similar to that of FIG. 15, except that the outboard axle bearing 332 f is a ball bearing, the bearing surface 606 f is a groove for receiving the bearing balls 604 f and the outer bearing race 360 f is formed in a single piece.

The example of FIG. 17 is similar to that of FIG. 16 except that it employs a four-point contact ball bearing for the outboard axle bearing 332 g in which the inner bearing races 620, 622 comprise bearing surfaces 606 g (i.e., grooves) that are formed directly into the shaft portion 366 g of the wheel flange 306 g. Additionally, the wheel flange 306 g employs a plurality of external spline teeth 650 that matingly engage internal spline teeth 652 on the shaft member 304 g to non-rotatably but axially movably couple the wheel flange 306 g to the shaft member 304 g.

In FIG. 18, a portion of another axle assembly constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral 22 h. The axle assembly 22 h can be generally similar to the axle assembly 22 (FIG. 2) except that the differential assembly 36 h includes a locking mechanism 700 that is configured to inhibit speed differentiation between the output members 242 h. The locking mechanism 700 can comprise a lock plate 702, a return spring 704, a first locking dog 706, a second locking dog 708, and a linear motor 710.

With additional reference to FIG. 19, the lock plate 702 can be formed of hardened stamped steel sheet or plate and can include a splined internal aperture 714 and an annular rim 716 that can be located concentrically about and radially outwardly of the splined internal aperture 714. The splined internal aperture 714 can define a plurality of spline teeth that can be non-rotatably but axially slidably engaged to mating splined teeth formed on one of the output members 242 h/side gears 284 h. The return spring 704 can be any device that can bias the lock plate 702 in a direction away from the differential pinions 282 and the pinion mount structures 252 h. In the particular example provided, the return spring 704 comprises a wave spring that is received over the one of the output members 242 h into a groove 720 formed on an axial end face of an associated one of the side gears 284 h. The first locking dog 706 can be fixedly coupled to the annular rim 716 of the lock plate 702. In the example provided, the first locking dog 706 comprises projections 724 that are formed when the lock plate 702 is stamped, but it will be appreciated that the first locking dog 706 could have teeth, pins or any other type of locking device that can be formed as a discrete component and assembled to the lock plate 702.

With reference to FIGS. 18 and 20, the second locking dog 708 can be coupled to the differential case 240 h and/or to the pinion mount structures 252 h. In the particular example provided, the second locking dog 708 is integrally formed with the pinion mount structures 252 h and comprises a plurality of recesses 728 formed into a side of the pinion mount structures 252 h that are configured to matingly receive the projections 724 (FIG. 19) of the first locking dog 706. In the example provided, the pinion mount structures 252 h are formed of powdered metal and as such, the recesses 728 are configured with draft to permit the dies (not shown) that are employed to form the pinion mount structures 252 h to be separated from one another to eject the pinion mount structures 252 h after they are formed.

Returning to FIG. 18, the linear motor 710 can be any type of device that is configured to translate the lock plate 702 along the second axis 42. In the particular example provided, the linear motor 710 is a solenoid and comprises a lock plate mount 730, an armature 732, a coil 734, and a coil mount 736. The lock plate mount 730 can be configured to couple the lock plate 702 to the armature 732 at least when the armature 732 is moved in a predetermined axial direction. In the particular example provided, the lock plate mount 730 is formed of a plastic material that is overmolded onto (i.e., cohesively bonded to) the armature 732. The lock plate mount 730 can define a radially inwardly extending lip member 740 that can be received about the annular rim 716 of the lock plate 702. The lip member 740 is not fixedly coupled to the annular rim 716 in the example provided, but is configured to contact the annular rim 716 when the armature 732 (and therefore the lock plate mount 730) is moved in an axial direction toward the coil 734. The armature 732 can be an annular structure that can be formed of a ferromagnetic material. The armature 732 can be generally L-shaped in cross-section with a sloped end 744 on its axially-extending leg 746. The coil 734 can be wound on a bobbin structure 748 that can be fixedly coupled to the coil mount 736.

With reference to FIG. 21, the coil mount 736 can comprise a plurality of cantilevered fingers 750. The cantilevered fingers 750 can have barbs (not specifically shown) at their distal ends that can be engaged in a snap-fit manner to a rim member 754 on the housing 30 h. The rim member 754 can comprise a section or strip of generally L-shaped sheet steel that can be welded to the second carrier member 64 h. Returning to FIG. 18, the coil mount 736 can include a coupling portion 756 that is configured to be coupled to a wire harness (not shown). The coupling portion 756 can be received into a boss 758 formed in the second carrier member 64 h. A seal 760 can be mounted to the coupling portion 756 and can be sealingly engaged to the coupling portion 756 and the boss 758 to inhibit the ingress of fluids into and the egress of fluid from the housing 30 h. While the particular linear motor described herein and illustrated in the appended drawings includes an electromagnet, it will be appreciated that other linear motors could be employed in the alternative, including pneumatic cylinders and hydraulic cylinders.

With reference to FIGS. 20 and 22, the pinion mount structures 252 h can be formed such that their ends 770 and 772 interlock with one another. Each of the ends 770 can comprise a plurality of first tabs 780 and a plurality of first recesses 782, while each of the ends 772 can comprise a plurality of second tabs 790 and a plurality of second recesses 792. Each of the second recesses 792 can be configured to receive a corresponding one of the first tabs 780, while each of the first recesses 782 can be configured to receive a corresponding one of the second tabs 790. The tabs and recesses on each of the ends 770 and 772 should be staggered such that the ends 770 and 772 interlock (and thereby support one another as is shown in FIG. 18) when adjacent pinion mount structures 252 h are assembled to one another.

In FIGS. 23 and 24, a portion of another axle assembly constructed in accordance with the teachings of the present disclosure is generally indicated by reference numeral 22 i. The axle assembly 22 i can be generally similar to the axle assembly 22 h (FIG. 18) except that the differential case 240 i is integrally formed with a case member 250 i and the pinion mounts 252 i. In the particular example provided, the differential case 240 i is a hollow tubular structure that is formed of a powdered metal material that is consolidated and heat-treated. The case member 250 i of the differential case 240 i can be fixedly coupled to the ring gear 34 by any desired method. In the particular example provided, a plurality of first teeth 800 on the case member 250 i are meshingly and matingly engaged with a plurality of second teeth 802 formed on a hub portion 804 of the ring gear 34 and the case member 250 i is additionally welded (e.g., laser welded) about its outer diameter to hub portion 804. While the differential case 240 i can extend through the hub portion 804, it need not extend completely through the entire ring gear 34 (e.g., the case member 250 i need not extend to a position radially inwardly of the ring gear teeth 806 that mesh with the pinion gear teeth 808 of the input pinion 32).

The pinion mounts 252 i can be configured to support the pinion members 290 of the differential pinions 282 for rotation relative to the case member 250 i about respective bevel pinion axes 298. Alternatively, the pinion mounts 252 i could be configured to receive a conventional cross-pin (not shown) onto which conventional bevel pinions (not shown) could be rotatably received. The conventional cross-pin can be fixed to the differential case 240 i in any desired manner, such as those described in commonly assigned U.S. Pat. No. 7,976,422 entitled “Differential With Cross Pin Retention System And Method For Assembly”, the disclosure of which is incorporated by reference as if fully set forth in detail herein.

Construction in this manner can be advantageous, for example, to permit the bearing elements 202 of the ring gear bearing 200 to be spaced-axially apart but disposed axially in-line along the second axis 42 with the case member 250 i, so that the differential assembly 36 i can be constructed in a radially compact manner in which the head bearing 96 is also disposed axially in-line with the case member 250 i along the second axis 42. In this arrangement, one of the axle shafts 38 that is coupled to one of the side gears 284 for rotation therewith extends through the ring gear 34, and the case member 250 i is disposed radially outwardly of and about the inboard axle shaft bearing 330 that supports the one of the axle shafts 38 relative to the first carrier member 54. Also in this arrangement, the ring gear 34 is positioned axially along the second axis 42: a) between the differential case 240 i and the input pinion 32; b) between the bevel pinions 282 and the input pinion 32; and c) between the side gears 284 and the input pinion 32.

While the axle assembly 22 i has been described and illustrated as being an axle assembly with an open differential assembly, those of skill in the art will appreciate that the axle assembly 22 i could optionally be equipped with a locking mechanism 700 (FIG. 18) that is configured to inhibit speed differentiation between the side gears 284. In this embodiment, the second locking dog 708 i comprises a plurality of teeth 728 i that are integrally formed with the differential case 240 i and configured to matingly engage corresponding teeth or projections 724 (FIG. 19) on the lock plate 702 (FIG. 18) of the first locking dog 706 (FIG. 18). Like the above-described embodiment, the lock plate 702 (FIG. 18) can be translated (e.g., via linear motor 710 (FIG. 18)) to selectively couple the differential case 240 i to the one of the output members 242 h/side gears 284 h (FIG. 18).

The example of FIG. 24A is generally similar to the example of FIGS. 23 and 24, except for the configuration of the differential assembly 36 i-1 and the mounting of the inboard and outboard axle shaft bearings 330 i and 332 i. The differential assembly 36 i-1 can include a unitarily formed differential case 240 i-1 and a differential gearset 280 c that has the cross-pin 550, differential pinions 282 c rotatably mounted on the cross-pin 550, and a pair of side gears 284 i-1. The differential case 240 i-1 can be splined to the ring gear 34 i-1 as described above and as such, can float axially along the second axis 42 relative to the ring gear 34 i-1.

The inboard and outboard axle shaft bearings 330 i and 332 i can be received pockets formed in the hub 212 i of the first carrier member 54 i and in the axle tube 66 i, respectively, and an axle shaft bearing preload nut 320 i can be threadably engaged to the axle shafts 38 i-1 at respective locations that are outboard of both the differential case 240 i-1 and the side gears 284 i-1. Additionally, the differential case 240 i-1 can pilot on a locating portion 38 i-2 of the outboard axle shaft 38 i-1. In this example, the differential case 240 i-1 can float in an axial direction along the second axis 42.

While the ring gear has been illustrated and described as including a single bearing, such as an annular contact bearing (e.g., a four-point contact ball bearing), it will be appreciated that the ring gear could be supported by a plurality of bearings. In FIG. 25 for example, the ring gear 34 j is supported by an inner ring gear bearing 200 j-1 and an outer ring gear bearing 200 j-2.

The inner ring gear bearing 200 j-1 can comprise a plurality of bearing elements 202 j-1, an outer bearing race 204 j-1, and an inner bearing race 206 j-1. The bearing elements 202 j-1 can be any type of element that can roll relative to the outer and inner bearing races 204 j-1 and 206 j-1. In the particular example provided, the bearing elements 202 j-1 comprise bearing balls. The outer bearing race 204 j-1 can comprise a bearing groove 210 j-1 that can be formed into a desired portion of the ring gear 34 j, such as the in the toe or inside diametrical surface of the ring gear 34 j. The bearing elements 202 j-1 can be received into the bearing groove 210 j-1 such that the outer bearing race 204 j-1 is unitarily and integrally formed with the ring gear 34 j. The inner bearing race 206 j-1 can be received on a hub 212 j formed on the first carrier member 54 j and abutted against a shoulder 1000. The inner ring gear bearing 200 j-1 can be an angular contact bearing.

The outer ring gear bearing 200 j-2 can comprise a plurality of bearing elements 202 j-2, an outer bearing race 204 j-2, and an inner bearing race 206 j-2. The bearing elements 202 j-2 can be any type of element that can roll relative to the outer and inner bearing races 204 j-2 and 206 j-2. In the particular example provided, the bearing elements 202 j-2 comprise bearing balls. The inner bearing race 206 j-2 can comprise a bearing groove 210 j-2 that can be formed into a desired portion of the ring gear 34 j, such as the in the outside diametrical surface of the ring gear 34 j. The bearing elements 202 j-2 can be received into the bearing groove 210 j-2 such that the inner bearing race 206 j-2 is unitarily and integrally formed with the ring gear 34 j. The outer bearing race 204 j-2 can be received in a counterbore 1002 formed in the second carrier member 64 j and abutted against a shoulder 1004 on the second carrier member 64 j. A threaded adjuster 1006 can be threadably engaged to the second carrier member 64 j and can be employed to generate a preload that is applied to the inner and outer ring gear bearings 200 j-1 and 200 j-2.

Alternatively, a plurality of ring gear bearings could be employed to support the ring gear, either from its inner side or its outer side. In the example of FIG. 26, first and second ring gear bearings 200 k-1 and 200 k-2 are employed to support the ring gear 200 k from its inner side.

The first ring gear bearing 200 k-1 can comprise a plurality of bearing elements 202 k-1, an outer bearing race 204 k-1, and an inner bearing race 206 k-1. The bearing elements 202 k-1 can be any type of element that can roll relative to the outer and inner bearing races 204 k-1 and 206 k-1. In the particular example provided, the bearing elements 202 k-1 comprise bearing balls. The outer bearing race 204 k-1 can comprise a bearing groove 210 k-1 that can be formed into a desired portion of the ring gear 34 k, such as the in the toe or inside diametrical surface of the ring gear 34 k. The bearing elements 202 k-1 can be received into the bearing groove 210 k-1 such that the outer bearing race 204 k-1 is unitarily and integrally formed with the ring gear 34 k. The inner bearing race 206 k-1 can be received on a hub 212 k formed on the first carrier member 54 k and abutted against a shoulder 1000 k. The first ring gear bearing 200 k-1 can be an angular contact bearing. A spacer 1010 can be disposed between the first and second ring gear bearings 200 k-1 and 200 k-2.

The second ring gear bearing 200 k-2 can comprise a plurality of bearing elements 202 k-2, an outer bearing race 204 k-2, and an inner bearing race 206 k-2. The bearing elements 202 k-2 can be any type of element that can roll relative to the outer and inner bearing races 204 k-2 and 206 k-2. In the particular example provided, the bearing elements 202 k-2 comprise bearing balls. The outer bearing race 204 k-2 can comprise a bearing groove 210 k-2 that can be formed into a desired portion of the ring gear 34 k, such as the in the toe or inside diametrical surface of the ring gear 34 k. The bearing elements 202 k-2 can be received into the bearing groove 210 k-2 such that the outer bearing race 204 k-2 is unitarily and integrally formed with the ring gear 34 k. The inner bearing race 206 k-2 can be received on the hub 212 k that is formed on the first carrier member 54 k. The second ring gear bearing 200 k-2 can be an angular contact bearing. A threaded adjuster 1006 k can be threadably engaged to the hub 212 k of the second carrier member 64 k and can be employed to generate a preload that is applied to the first and second ring gear bearings 200 k-1 and 200 k-2.

The foregoing description of the embodiments has been provided for purposes of illustration and description. It is not intended to be exhaustive or to limit the disclosure. Individual elements or features of a particular embodiment are generally not limited to that particular embodiment, but, where applicable, are interchangeable and can be used in a selected embodiment, even if not specifically shown or described. The same may also be varied in many ways. Such variations are not to be regarded as a departure from the disclosure, and all such modifications are intended to be included within the scope of the disclosure. 

1-32. (canceled)
 33. An axle assembly comprising: a housing that defines an internal cavity, an output axis and an annular hub; an annular gear received in the internal cavity; a four-point angular contact bearing having an inner bearing race, which is mounted on the annular hub, an outer bearing race, which is fixedly coupled to the annular gear, and a plurality of bearing balls that are received between the inner and outer bearing races, the four-point angular contact bearing supporting the annular gear relative to the housing for rotation about the output axis; a differential assembly received in the internal cavity, the differential assembly having a differential input member, which is coupled to the annular gear for rotation therewith, and first and second differential output members that are rotatable relative to the differential input member about the output axis; a first output shaft that is coupled to the first differential output member for rotation therewith; and a second output shaft that is coupled to the second differential output member for rotation therewith, the second output shaft extending through the annular hub on the housing.
 34. The axle assembly of claim 33, wherein the inner bearing race comprises discrete first and second race members.
 35. The axle assembly of claim 33, wherein at least one threaded fastener is employed to secure the inner bearing race to the housing.
 36. The axle assembly of claim 35, wherein the at least one threaded fastener comprises a nut that is threaded to a threaded portion of the annular hub.
 37. The axle assembly of claim 33, wherein the annular hub defines a shoulder, and wherein the inner bearing race is abutted against the shoulder.
 38. The axle assembly of claim 33, wherein at least a portion of the outer bearing race is unitarily and integrally formed with the annular gear.
 39. The axle assembly of claim 33, wherein the annular gear is a bevel gear.
 40. The axle assembly of claim 33, wherein the annular gear is meshed with another gear that is rotatable about an axis that is transverse to the output axis.
 41. The axle assembly of claim 33, wherein the differential input member is a differential case, wherein the differential assembly includes a differential gearset that is received in the differential case.
 42. The axle assembly of claim 41, wherein the first and second differential output members are side gears in the differential gearset.
 43. The axle assembly of claim 42, wherein the differential gearset includes a plurality of differential pinions that are coupled to the differential case for rotation therewith.
 44. The axle assembly of claim 43, wherein each of the side gears meshingly engages each of the differential pinions.
 45. The axle assembly of claim 33, wherein the differential input member is fixedly coupled to the annular gear.
 46. An axle assembly comprising: a housing that defines an internal cavity, an output axis and an annular hub; an annular gear received in the internal cavity; a four-point angular contact bearing having an inner bearing race, which is mounted on the annular hub, an outer bearing race, which is fixedly coupled to the annular gear, and a plurality of bearing balls that are received between the inner and outer bearing races, the four-point angular contact bearing supporting the annular gear relative to the housing for rotation about the output axis; a differential assembly received in the internal cavity, the differential assembly having a differential case and a differential gearset that is housed in the differential case, the differential case being fixedly coupled to the annular gear, the differential gearset including a plurality of differential pinions, which are coupled to the differential case for rotation therewith, and a pair of side gears that are drivingly engaged to the differential pinons; a first output shaft that is coupled to a first one of the side gears for rotation therewith; and a second output shaft that is coupled to a second one of the side gears for rotation therewith, the second output shaft extending through the annular hub on the housing.
 47. The axle assembly of claim 46, wherein the inner bearing race comprises discrete first and second race members.
 48. The axle assembly of claim 46, wherein at least one threaded fastener is employed to secure the inner bearing race to the housing.
 49. The axle assembly of claim 48, wherein the at least one threaded fastener comprises a nut that is threaded to a threaded portion of the annular hub.
 50. The axle assembly of claim 46, wherein the annular hub defines a shoulder, and wherein the inner bearing race is abutted against the shoulder.
 51. The axle assembly of claim 46, wherein at least a portion of the outer bearing race is unitarily and integrally formed with the annular gear.
 52. The axle assembly of claim 46, wherein the annular gear is a bevel gear.
 53. The axle assembly of claim 46, wherein the annular gear is meshed with another gear that is rotatable about an axis that is transverse to the output axis.
 54. The axle assembly of claim 46, wherein each of the side gears meshingly engages each of the differential pinions.
 55. An axle assembly comprising: a housing that defines an internal cavity, an output axis and an annular hub; an annular gear received in the internal cavity; a four-point angular contact bearing having an inner bearing race, which is mounted on the annular hub, an outer bearing race, which is fixedly coupled to the annular gear, and a plurality of bearing balls that are received between the inner and outer bearing races, the four-point angular contact bearing supporting the annular gear relative to the housing for rotation about the output axis; a differential assembly received in the internal cavity, the differential assembly having a differential case and a differential gearset that is housed in the differential case, the differential case being fixedly coupled to the annular gear for rotation therewith, the differential gearset including a plurality of differential pinions, which are coupled to the differential case for rotation therewith, and a pair of side gears that are drivingly engaged to the differential pinons; a first output shaft that is coupled to a first one of the side gears for rotation therewith; and a second output shaft that is coupled to a second one of the side gears for rotation therewith, the second output shaft extending through the annular hub on the housing; wherein the annular hub defines a shoulder, and wherein the inner bearing race is abutted against the shoulder; wherein at least a portion of the outer bearing race is unitarily and integrally formed with the annular gear.
 56. The axle assembly of claim 55, wherein the inner bearing race comprises discrete first and second race members.
 57. The axle assembly of claim 55, wherein at least one threaded fastener is employed to secure the inner bearing race to the housing.
 58. The axle assembly of claim 57, wherein the at least one threaded fastener comprises a nut that is threaded to a threaded portion of the annular hub.
 59. The axle assembly of claim 55, wherein the annular gear is a bevel gear.
 60. The axle assembly of claim 55, wherein the annular gear is meshed with another gear that is rotatable about an axis that is transverse to the output axis.
 61. The axle assembly of claim 55, wherein each of the side gears meshingly engages each of the differential pinions. 